Methods that are called on a class instead of on an object.
Class methods are methods that are called on a class (compare this to class instance methods, or object methods). Its meaning may vary depending on the programming language: In some languages (e.g. C++, Java), class methods are synonymous with static methods (see section below), which are called with a known class name at compile-time. this cannot be used in static methods.
In some other languages (e.g. Smalltalk, Ruby, Objective-C), class methods are methods that are called on a class object, which can be computed at runtime, there being no difference between calling a method on a regular object or a class object; thus both instance and class methods are resolved dynamically, and there are no "static" methods. Notably, in these class methods, this refers to the class object.
Some languages have both. For example, in Python, one can create class methods and static methods using the classmethod and staticmethod decorators, respectively. The former has access to this (i.e. the instance object, conventionally known as self), while the latter does not.
